Protected electrical apparatus



July 13, 1965 J. J. ASTLEFORD, JR.. E'I'AL 3,195,015

PROTECTED ELECTRICAL APPARATUS Original Filed May 12, 1959 4Sheets-Sheet 1 Fig.|

Fig .3.

ATTORNEY I L I k 63A 396 36 s"! 12m 86 348 422 T g3 see as .342 92 Y 6531s 17 I I 65A 4: 374

July 13, 1965 J. J. ASTLEFORD, JR., ETAL 3,195,015

PROTECTED ELECTRICAL APPARATUS Original Filed May 12, 1959 4 h h e 5 F\U f 34s 61 358 64 64A426 as 344fi Fig.8. 3; 358 3 6 362 382 -19 EV J y3, 1965 J. J. ASTLEFORD, JR.. ETAL 3,195,015

PROTECTED ELECTRICAL APPARATUS Original Filed May 12, 1959 4Sheets-Sheet 4 United States Patent 3,195,015 PRUTEQTED ELECTRECALAPPARATUS John J. Astleford, r., Sharon, Pa., and Thomas P. Henry,

Masury, and Merrill G. Leonard, Fowler, Ghio, as-

signors to Westinghouse Electric Corporation, East Pittsburgh, Pin, acorporation of Pennsylvania Continuation of applications Ser. No.812,632, May 12,

1959, new Patent No. 3,126,500, dated Mar 24, 1964,

and Ser. No. 812,633, May 12, 1959. This application Sept. 22, 1960,Ser. No. 57,772

9 Claims. (Cl. 317--14-) This invention relates generally to protectedelectrical apparatus, and more particularly, to protected apparatus fortransformers.

This application is a continuation of our copending applications SerialNo. 812,632, now Patent No. 3,126,500, and Serial No. 812,633, nowabandoned, which were both filed May 12, 1959 and which are bothassigned to the same assignee as this application.

In conventional electrical power systems in which distributiontransformers of the self-protected typeare coinimonly connected betweena high voltage supply or feeder circuit and a low voltage distributionor load circuit, circuit breakers are provided Within the transformersfor disconnecting the transformer from the distribution circuit upon theoccurrence of predetermined load conditions in the transformer. Intransformers which operate in a cooling and insulating fluid or liquiddielectric, such as oil, a thermally responsive or temperatureresponsive means or element or a number of such elements may be employedfor actuating the associated circuit breaker to rotect the transformerfrom the damage which results from overheating caused by overloading thetransformer. Theranally responsive means, such as bimetallic elements ordevices, may be used for the latter purpose and may be so located ordisposed that they are immersed in the insulating liquid or fluid andheated both in accordance with the temperature of the insulating fluidand in accordance with the current flowing in the transformer secondarycircuit. The insulating fluid temperature or thermal condition is afunction of the heating of the transformer core and coils over aprolonged or considerable period of time and current flowing at anyparticular time has a more direct effect on the heating of thetransformer which is taking place at the latter time rather than over aprolonged period of time. By properly coordinating the relative effectsof the long time loads as indicated by the fluid or liquid temperatureand the short time loads as indicated by the instantaneous currentflowing in the secondary winding of a transformer, the thermallyresponsive or temperature responsive means or elements can be maderesponsive to the copper temperature or winding temperature of saidtransformer in a well-known manner.

In a conventional, selfprotected distribution transformer of the typedescribed, the operation of the circuit interrupter is actuated throughsuitable mechanical means upon the operation of an associated thermallyresponsive means, such as a bimetallic element. In other words, upon theoccurrence of a predetermined load or operating condition in thetransformer, the operation or deformation of a conventional thermallyresponsive means, such as a bimetallic element, is mechanicallyamplified by suitable tripping means to actuate an associated circuitinterrupter and interrupt the secondary circuit of said transformer.Examples of conventional protective devices of the type described aredisclosed in US. Patent 2,223,- 530 and in US. Patent 2,586,429 filed byJ. K. Hodnette et al. and assigned to the same assignee as the presentapplication. As the desired ratings of conventional electricalapparatus, such as distribution transformers, of the selfprotected type,increase, the load currents which must be interrupted by the associatedcircuit interrupter and the mechanical forces involved also increase toa corresponding degree. Because of the large mechanical forcesinvolvedin interrupting load currents associated with distribution transformershaving higher ratings, it has been found that certain mechanicalproblems arise in providing suitable mechanical means or tripping meansfor actuating a circuit interrupter to a circuit interrupting positionin response to or upon the operation of a conventional thermallyresponsive means. It is therefore desirable to provide a distributiontransformer of the self-protected type in which the latter mechanicalproblems are substantially eliminated and in which several otheradvantages are obtained.

It is an object of this invention to provide a new and improvedelectrical transformer including means for indicating and protectingsaid transformer against predetermined load conditions in thetransformer.

Another object of this invention is to provide a new and improvedelectrical transformer in which an associated circuit interrupter isactuated by electrically operated means in response to the operation ofan associated thermally responsive means.

A more specific object of the invention is to provide a new and improvedelectrical transformer, including signalling means for indicating apredetermined load condition in said transformer, a circuit interrupterhaving electrically operated tripping and reclosing means, and manuallyoperable means for controlling the operation of said tripping andreclosing means.

Other objects of the invention will, in part, be obvious and will, inpart, appear hereinafter.

For a fuller understanding of the natur and objects of the inventionreference should be had to the detailed description taken in connectionwith the accompanying drawings, in which:

FIGURE 1 is a simplified view, partly in section and partly in sideelevation, of a transformer showing protective apparatus applied theretoin accordance with the teachings of this invention;

FIG. 2 is a diagrammatic view of circuits and apparatus comprising thetransformer shown in FIG. 1;

FIG. 3 is a side elevational view of the manually operable means foroperating the circuit interrupt-er associated with the transformer shownin FIG. 1, taken along the line IIL-III in FIG. 1, in the neutralposition;

FIG. 4 is a side elevational view of the exterior ortion of the manuallyoperable mean-s shown in FIG. 3 taken along the line IVIV in FIG. 1;

'FIG. 5 is a sectional View of the manually operable means shown inFIGS. 3 and 4 taken along the line V--V in FIG. 4;

FIG. 6 is a side elevational view of the exterior portion of analternate embodiment of the manually operable means shown in FIGS. 3through 5.

FIG. 7 is a partial top plan View of a thermally responsive deviceembodying the principles of the invention with the leads of theassociated electrical apparatus shown in phantom;

FIG. 8 is a sectional view taken along the line VIII VIII of FIG. 7 andlooking in the direction of the ar- FIG. 12 is a partial elevationalview, taken along the line XII-XIX in FIG. 11, and looking in thedirection of the arrows.

Referring now to the drawings and FIGS. 1 and 2 in particular, there isillustrated a transformer 1%} having a tank or casing 4e enclosing ahigh voltage or primary Winding 33 and a low voltage or secondarywinding &2, including first and second low voltage winding portions 42Aand 423, said windings being inductively disposed on a magnetic corestructure 4-4 including first and second magnetic core members 44A and441%. The windings 38 and 42 together with the magnetic core members 44Aand 44B comprise a core and coil assembly which is maintained inassembled relationship by a generally U- shaped, wrap-around end framestructure 52, the ends of which are connected by a horizontal member 55,as best shown in FIG. 1. A sufiicient quantity of dielectric fluid, suchas oil, is employed to at least partially fill the casing 46 andpreferably to substantially immerse the windings 38 and 42 and themagnetic core structure 44.

The primary winding 38 of the transformer 14 is connected through thebushings 12 and 14- which pass through the casing as to a source ofelectrical energy represented by the supply conductors 13 and 15. Thesecondary winding portions -Z A and 42B are connected to thedistribution circuit conductors 22 and 24 and 26 and 23, respectively,by the secondary leads 82 and 84 and 86 and $5, respectively. As shownin FIG. 1 the distribution circuit conductors or terminals 22 and 23 areconnected to the associated secondary leads through the secondarybushings or terminal connectors 52 and 58, respectively, which passthrough the casing 46. The distribution circuit conductors or terminals24 and 26 may be connected to the associated secondary leads $4 and 86,respectively, at a common terminal, as indicated at the terminalconnector or low voltage bushing 54, shown in FIG. 1. In other words,one end of each of the secondary winding portions 42A and 4?) may beconnected by the secondary leads 84 and S6 and the associateddistribution circuit conductors 24 and 26 to a common junction point orterminal 5-4, as shown in FIG. 1. The terminal connector 54 may be aneutral or ground terminal. It is to be understood that in differentapplictions that the secondary winding portions 42A and 428 may beconnected either in parallel circuit relationship or series circuitrelationship with respect to each other.

In general, a circuit interrupter, more specifically a reclosablecircuit breaker, indicated at 1%, is provided Within the casing 4-6 ofthe transformer having circuit interrupting contact members 122 and 128that are connected in series circuit relationship with the secondaryleads 32 and 38, respectively, and mechanically connected to operatetogether, as illustrated. The thermally responsive means 5% is providedfor effecting the actuation or operation of the circuit breaker 100under certain predetermined operating conditions of the transformer 10.In addition, a signalling means or circuit 119 including an indicatinglamp 7%, which is visible eXteriorly of the easing 46, is generallydisposed within said casing. The thermally responsive means 59 alsoeffects the actuation or energization of the signalling means 111) undercertain predetermined operating conditions of the transformer 10. Amanually operable means 21%, including an operating handle, which isavailable or accessible exteriorly of the casing 46, for actuating thecircuit breaker 1% to circuit opening or circuit closing positions andfor resetting the signalling means 1'10 after operation of saidsignalling means is also provided for the transformer It In order tosupply the electric current or power required for the operation or" thecircuit breaker res and the signalling means 11%), a coil or winding 45including first and second coil portions 45A and 45B is inductivelydisposed on the magnetic core structure 44- of the transformer 1d andloosely coupled electromagnetically with the windings 38 and 42 of saidtransformer. As disclosed in greater detail in US. Patent 2,298,126,filed by I. K. Hodnette and assigned to the same assignee as the presentapplication for a similar coil employed in a signalling system fortransformers, the coil portions 45A and provide substantially apredetermined voltage to the associated circuit breaker 1% and thesignalling means 219 independently of the position of the contactmembers 122 and 128 of said circuit breaker whenever a suitable supplyvoltage is applied to the primary winding of the transformer 1b andwithout subjecting the components of said circuit breaker and signallingmeans to damage due to overvoltages which may result when surge voltagesare present on the windings 33 and 42 of said transformer during certainabnormal operating conditions.

The circuit breaker 1% may be of any suitable type of circuit breakerwhich may be actuated to a circuit interrupting position when energizedby the operation or" the thermally responsive means 59 or the manuallyoperable means 210 and which may be actuated to a circuit closingposition when electrically energized by the operation of the manually oerable means 219. In particular, the circuit breaker 1% is preferably ofthe general type which is disclosed in our copending application SerialNo. 801,843, filed March 25, 1959 which issued August 1, 1961 as US.Patent No. 2,994,753 and is assigned to the same assignee as the presentapplication.

Referring to FIG. 2, the circuit breaker 1% is shown diagrammaticallywith the contact members of said circuit breaker in the circuit closingposition. The contact members 122 and 123 of the circuit breaker 1% aredisposed or mounted on a movable contact arm 132 which is mechanicallycoupled or linked to the toggle mechanism 162, the toggle mechanism 1&2being shown in the position corresponding to the circuit closingposition of the contact members 122 and 128. The movable contact arm orswitch operating member 132 is biased in the downward direction by thespring 163 for reasons which will be explained hereinafter. An auxiliarycontact member 134, which is normally opened when the associated contactmembers 122 and 128 are in the closed position, is also mounted ordisposed on tie movable contact arm 132.

The circuit breaker 1% also includes an electrically operated trippingmeans, more specifically the tripping solenoid 15%, which may beenergized from the loosely coupled coil 45, either upon the operation ofthe thermally responsive means 559 or upon the operation of the manuallyoperable means 216. The tripping solenoid 1.59 comprises an operatingcoil 152 and a plunger or tripping member 154 which engages a projectionor catch 153 on the latch rod 166 when said operating coil isdeenergized to thereby prevent the trip biasing spring 168 from movingthe latch rod 156 to the left and actuating the toggle mechanism 162 andmovable Contact arm 152, as well as the contact member 122 and 128 ofthe circuit breaker 1%, to the circuit interru ting position. Thegripping solenoid 15% also includes a contact member -oo which isnormally closed when the operating coil 152 of said solenoid isdeenergized, for reasons which will be explained hereinafter. The upperend of the operatmg C011 152 of the solenoid 15% is electricallyconnected to the stationary contact 65 of the thermally responsive meansS'l) and also to the terminal 222 of the manually operable means are inorder that said solenoid may be energized upon the operation of saidthermally respons1ve means or upon the operation of said manuallyoperable means. The lower end of the operating coil 152 of the trippingsolenoid 151 is connected to the terminal which is connected in turn tothe lower end of the loosely coupled coil 45.

The circuit breaker 1% also preferably includes an electrically operatedreclosing means, more specifically the reclosing solenoid 142, which ingeneral is arranged to be energized by the operation of the manuallyoperable means 210 to actuate the contact members 122 and 128 of saidcircuit breaker to circuit closing positions. The reclosing solenoid 140comprises an operating coil 142 and a plunger 144 which is moved to theright when said operating coil is energized. The operating coil 142 ofthe reclosing solenoid 14'!) is connected in series circuit relationshipwith the normally closed contact 156 of the tripping solenoid 150, theseries circuit being connected between the terminal 214 of the manuallyoperable means 210 and the terminal 75 which is connected in turn to thelower end of the loosely coupled coil 45.

During the operation of the circuit breaker 160, when the trippingsolenoid 150 is energized by either the thermally responsive means 55)or the manually operable means 219, the tripping member 154 of thesolenoid 150 is moved in an upward direction by the operating coil 152to disengage the projection or catch 158 on the latch rod 166. When thetrip member 154 disengages the catch 15%, the trip bias spring 163 movesthe latch rod 166 to the left causing the toggle mechanism 162 to alsomove to the left and permitting the biasing spring 163 to cooperate withthe trip bias spring 168 to actuate said toggle mechanism and themovable contact arm 132, as well as the contact members 122 and 128, tocircuit interrupting positions. Energizing the operating coil 152 of thetripping solenoid 150 also opens the normally closed contact 156 of saidsolenoid which is connected in series circuit relation with theoperating coil 142 of the reclosing solenoid 140 to thereby preventenergization of the reclosing solenoid 1 21) so long as the operatingcoil 152 of the tripping solenoid 156 is energized.

On the other hand, after the circuit breaker 100 has been actuated to acircuit interrupting position by the energization of the trippingsolenoid 150, the circuit breaker 160 can be restored to a circuitclosing position by the operation of the manually operable means 210 toenergize the reclosing solenoid 141), assuming that the operating coil152 of the tripping solenoid 150 is now deenergized. Energizing theoperating coil 142 of the reclosing solenoid 140 causes the plungermember 164 to move to the right to reset the toggle mechanism 162 and toactuate the movable contact arm 132, as well as the contact members 122and 128, to circuit closing positions. The resetting of the togglemechanism 162 by the reclosing solenoid 140 in turn resets the latch rod166 whose projection or catch 158 is again engaged by the trippingmember 154 of the tripping solenoid 150 assuming, as just mentioned,that the operating coil 152 of said tripping solenoid is nowdeenergized. It is to be noted that the circuit breaker 104), as Well asthe contact members 122 and 128 of said circuit breaker, are preferablyarranged to be immersed in the insulating or cooling fluid, as bestshown in FIG. 1, in order to improve arc interruption when said circuitbreaker is actuated to a circuit interrupting position.

Referring to FIGS. 1 and 2 and as described in our copending applicationSerial No. 812,632 filed May 12, 1959, and assigned to the same assigneeas the present application, the thermally responsive means 50 comprisesfirst and second thermally responsive elements, more specifically thebimetallic strip members 64 and 66, respectively, and current responsivemeans, more specifically the first and second current transformers orpick-up coils 62A and 628, respectively, which are non-ferromagneticallycoupled to or disposed in inductive relationship with the secondaryleads 86 and 84, respectively, from the secondary winding portions 42Band 42A, respectively. It

is to be understood that, in certain applications, the pickup coils 62Aand 62B may be combined in a single pickup coil 62 having first andsecond winding portions 62A and 62B disposed adjacent to the leads 86and 84, respectively, and effectively connected in series circuitrelationship.

are connected in series circuit relationship to produce an outputcurrent at the conductors 6'7 and 69 which varies with the sum of theload currents flowing in the secondary leads 86 and 84, respectively.The first and second bimetallic members 64 and 66 are also connected inseries circuit relationship, the series circuit comprising a burden orload across the output conductors 67 and 69 of the current transformersor pick-up coils 62A and 623. The current which flows through the firstand second bimetallic members 64 and 66 and the corresponding heating ofsaid bimetallic members due to said current, therefore, varies with theload current flowing in the secondary leads 86 and 84, and the secondarywinding portions 42A and 4213, respectively, the sum of said currentsbeing effective to heat said bimetallic members. As best shown in FIGS.1 and 10, the thermally responsive means 50 is substantially immersed inthe insulating or cooling fluid inside the casing 46 of the transformer10 and the temperature or thermal condition of the bimetallic members 64and 66 also varies with the temperature or thermal condition of saidfluid. The total temperature or thermal condition of the bimetallicmembers 64 and 66, therefore, varies with both the load current flowingin the secondary winding portions 42A and 4213, as sensed by the currenttransformers or pick-up coils 62A and 6213 in the secondary leads 36 and8 respectively, and with the tel perature or thermal condition of theinsulating or cooling fluid inside the casing 46. As explainedpreviously, for slowly changing load conditions of the transformer 16during normal operating conditions and for moderate overload conditionsup to approximately two to three times rated load current, thetemperature or thermal condi'tion of the insulating or cooling fluidinside the casing 46 closely follows the copper or Winding temperatureof the windings of the transformer 10 and controls the temperature orthermal conditions of the bimetallic members 64 and 66 to a much greaterdegree than the current flow through said bimetallic members. For muchhigher overload currents flowing in the secondary leads 86 and 8-4 of ashort time nature, the temperature or thermal conditionof the bimetallicmembers 64 and 66 is controlled to a much greater degree by the currentflow in said bimetallic members, rather than by the temperature orthermal condition of the insulating or cooling fluid in the casing 46 inorder that the thermally responsive means 50 more closely follow thecopper or Winding temperature or thermal condition of the transformer 16during the latter abnormal operating condition.

In general, the first bimetallic member 64 of the thermally responsivemeans 56 is connected in circuit relation with the signalling means 110to actuate the operation of said signalling means upon the occurrence ofa first predetermined operating or thermal condition of the transformerIt). The second bimetallic member 66 of the thermally responsive means56 is connected in circuit relation with the circuit breaker in order toactuate said circuit breaker to a circuit interrupting position upon theoccurrence of a second predetermined operating or load condition of thetransformer 10. The first bimetallic member 64 is preferably arranged tobe responsive to a lower temperature or thermal condition than thesecond bimetallic member 66, for reasons which will be explainedhereinafter.

in particular, the right-hand or fixed ends of the bimetallic members 64and 66 are mounted on suitable abutments 61A and 61B, respectively, inthe thermally responsive device 50 and electrically connected to theoutput conductors 6'7 and 69, respectively, of the current transformersor pick-up coils 62A and 62B, respectively. The left-hand, free ormovable ends of the bimetallic members 64 and 66 are both connected to acommon junction point or terminal, as indicated at 77, which is 65increases, said bimetallic members deflect or deform and the free end ofeach of said bimetallic members moves in an upward direction to formfirst and second switching means with the associated stationary contactmembers 63 and 65, respectively, which are actuated by said bimetallicmembers. The stationary contact member 63 is connected to the terminal59 which is connected in turn to the conductor 233 in the signallingmeans 110. The stationary contact member 65 is connected to the upperend of the operating coil 152 of the tripping solenoid 158 in thecircuit breaker lid-ii and to the terminal 232 in the manually operablemeans 219, as previously mentioned.

As disclosed in our copending application Serial No. 312,632 previouslymentioned and as best shown in FIGS. 7 through 9, the t' ermallyresponsive device 56 comprises a base member 49, which is preferablymolded from a suitable molding material, such as a glass polyester typeof molding material. The base member 40 includes a main portion 344-,which is generally rectangular in shape, a terminal plate portion 343,which projects generally upwardly from said main portion, a generallycup-shaped cavity or recess 346, a slot or recess 338 which extendsaround and is adjacent to the periphery of said main portion, andmounting feet or extensions 342 at the opposite ends of said basemember. In order to form a closed chamber or housing in the upperportion of the cavity 34-6, for reasons which will be discusedhereinafter, a partition or divider member 362 is disposed inside saidcavity and sealed to the shoulder portion 358 of the base member 4i! ina substantially fluid-tight joint by a suitable sealing or bondingmaterial, such as an epoxy resin. The partition or cover member 362 ispreferably formed from a material having a high thermal conductivity,such as a metal.

The pick-up coil or current transformer winding 62 is disposed in theslot 338 of the main portion 44 of the base member if as best shown inFIGS. 7 and 8, and includes a plurality of turns of an insulatedconductor which are disposed in inductive relationship with ornonferromagnetically coupled to the adjacent secondary leads 86 and 64of the transformer 16. The pick-up coil 62 includes first and secondwinding portions 62A and 62B, respectively, which are disposed adjacentto the secondary leads 86 and $4, respectively, and effectivelyconnected in series circuit relationship so that the output currentinduced in said pick-up coil when current flows in one or both of thesecondary leads 86 and 84 varies with the sum of the currents in saidsecondary leads and the associated windings of the transformer it). Asbest shown in FIGS. 7 and 8, the plane of the coil 62 is substantiallyparallel to and close to the plane of the conductors 84 and 86 so thatthere is good mutual coupling there'oetween, in contrast with thesubstantially negligible mutual coupling that would exist if the coilwere at or near a right angle with respect to the conductors. The outputcurrent of the pick-up coil 62 which appears at the output condctors 67and 69 is applied to the bimetallic elements 64 and 66 through suitableClipon type terminal connectors 364 and 3'74, respectively, which areelectrically connected to the terminal members 366 and 376,respectively, which in turn are electrica lly connected to the ends ofthe bimetallic elements 64- and 66, res-pectivley, by the rivets 382 and384, respectively. It is important to note that due to the absence of aferromagnetic core associated with the winding portions of the pick-upcoil 62 that the output current of said pick-up coil varies in asubstantially linear manner with the sum of the currents in thesecondary leads 3-6 and 84 even during certain abnormal operatingconditions of the transformer it), such as during short circuit or faultconditions at the distribution circuit terimnals 22, 2 26 and 23. It isto be understood that in certain applications, separate or individualpickup coils or current transformer windings may be provided E) U foreach of the secondary leads 8:? and 84, rather than a single pick-upcoil as shown in FIGS. 1, 7 and 8.

The bimetallic elements as and 66 are preferably iounted or disposedinside the sealed chamber 356 of the base member 49 with one end of eachof said bimetallic elements fixed or secured to the abutment or shoulder61 of said base member by suitable fastening means, such as the rivets382 and 3-34, respectively. The other or free ends of each of thebimetallic elements 64 and 6d are electrically connected to the commonjunction point or terminal 77 by the flexible conductors 378 and 388,respectively, through a connecting terminal 26 and a rivet 422 whichalso functions as a suitable fastening means for securing the terminalsass and 4-26 to opposite sides of the terminal plate portion 348 of thebase member 4d, as best shown in FIG. 8. The common junction point orterminal '77 is also connected to associate signaling or protectiveequipment by the conductor 1%, as shown in FIG. 1. The bimetallicelements 64- and 66 are arranged to deflect or deform as the temperatureor thermal condition of the transformer It; changes with the free endsof the bimetallic elements 64 and 66 arranged to move in an upwarddirection to actuate the associated contact means 90 upon the occurrenceof predetermined thermal load or operating conditions in the transformer14]. The temperature or thermal condition of the bimetallic elements 64and 66 varies primarily with the temperature of the insulating fluid11th of the transformer it for slowly changing load conditions of saidtransformer and primarily with the current flow in the secondary leadsand 84 and the associated windings of said transformer for rapidlychanging load conditions of the said transformer, particularly whenlarge overload currents are flowing in the windings of said transformer.The bimetallic elements 64 and 66 may the arranged to actuate associatedcontact means upon the occurrence of substantially the same temperatureor thermal condition of the transformer It) or upon the occurrence ofdifferent predetermined thermal conditions or temperatures of saidtransformer. For example, the bimetallic element 64 may be arranged toactuate the contact means and an associated signaling means, such as theindicating lamp 78, upon the occurrcnce of a first predetermined thermalconditions of the transformer 10 and the bimetallic element 65 may bearranged to actuate the contact means 90 and an associated protectivemeans, such as the circuit breaker 100, upon the occurrence of a secondpredetermined thermal condition of the transformer It}, which ispreferably higher than the first predetermined thermal condtion.

In order to reduce the size of the bimetallic elements 64 and 66required in the thermally responsive device 59, the space in the sealedchamber 356 of the base member 44 is preferably at least partiallyfilled with a suitable material, such as air, having a lower thermalconductivity than the insulating fluid did of the transformer ltl. Thelatter arrangement reduces the heat transfer or loss from the bimetallicelements 64 and 66 during certain operating conditions such as when theload on the transformer it is changing rapidly and the heating of saidbimetallic elements is being controlled primarily by the currnet flow inthe secondary leads 86 and S4 and the corresponding output current ofthe pickup coil 62. As mentioned previously, the :latter conditionoccurs primarily when the secondary leads 86 and 84 are carrying highoverload currents. In general, the latter arrangement also reduces therequired current through said bimetallic elements to obtain apredetermined heating of said elements and increases the overall thermalefiiciency of the device 50.

The contact means 94? comprises the movable contact members 64A and 66A,which are mounted or disposed on the free ends of the bimetallicelements 64- and 65, respectively, or formed integrally with saidbimetallic ele ments, and the associated stationary contact members 63 9and 65, respectively, which are mounted on the terminal plate portions348 of the base member 40 and secured thereto by suitable fasteningmeans, such as the rivets 396 and 416, respectively. The stationarycontact members 63 and 65 include the adjustable contact posts or setscrew contact members 63A and 65A, respectively. The adjustable contactposts 63A and 65A threadably engage the lower portion of the stationarycontact members 63 and 65, respectively, and pass through the terminalplate portion 348 of the base member 40 into the chamber 356, the lowerends :of the adjustable contact posts 63A and 65A being arranged to beengaged by the associated movable contact members 64A and 66A,respectively, upon the occurrence of predetermined load or operatingconditions in the transformer 10. The distance or separation between theadjustable contact posts 63A and 65A and the associated movable contactmembers 64A and 66A, respectively, may be varied by the setting of saidadjustable contact posts in order to vary the deflection required by theassociated bimetallic members 64, 66, respectively, as well as thecorresponding thermal conditions of the transformer 10, to cause saidcontact members to be engaged or actuated to a circuit closing positionfor calibration purposes or to adjust the thermally responsive devicefor use with different ratings of associated electrical apparatus. Thestationary contact members 63 and 65 are connected in circuit relationwith associated signaling or protective equipment as shown in FIG. 2 bythe conductors 104 and 108, respectively, so that when the bimetallicelements 64 or 66 actuate the movable contact members 64A and 66A,respectively, of the contact means 90 to circuit closing positions,closed circuits are formed between the common conductor 106 and eitherthe conductor 104 or the conductor 108, respectively. The forming of theclosed circuits just described by the thermally responsive device 50 inresponse to predetermined operating conditions of the transformer 10 mayconveniently serve to energize or actuate electrically operatedsignaling or protective equipment, as previously mentioned, byconnecting said equipment to a suitable source of electrical current.

The spacing between the pick-up coil 62 in the thermally responsivedevice Sit and the leads of the associated electrical apparatus, such asa distribution transformer, has been found to be critical in order toobtain the best operating characteristics of said device and in orderthat the thermal characteristics of said device correspond more closelyto the thermal condition or copper temperature of the associatedelectrical apparatus. Referring now to FIGS. 10 through 12, there isillustrated means for mounting the thermally responsive device 50 on theleads 86 and 84 of the transformer 10 andfor maintaining substantially apredetermined spacing between the pick-up coil 62 of said device andsaid leads and, therefore, for maintaining substantially a uniformelectromagnetic coupling between said leads and said device duringsubstantially all operating conditions of the transformer 10.

In particular, the clamping or mounting means 439 is provided at eachend of the thermally responsive device Stl, as best shown in FIG. 10. Asbest shown in FIGS. 11 and 12, the clamping means 430 comprises a pairof cooperating block or strap members 434A and 434B for clamping one endof the thermally responsive device 50 to the leads 86 and 84 of thetransformer 10. As shown in FIG. 11, the block or strap member 434Aincludes a first larger recess 438 which accommodates the leads 86 and84 and a portion of one of the feet 342 and a second smaller recess 437which accommodates a portion of one of the feet 342 of the thermallyresponsive device 50 which is disposed between the leads 86 and 84 andbetween the block 101 strap members 434A and 4348. The extremities orouter ends of the strap or block members 434A and 434B are preferablyheld together or secured by suitable means, such as the bolts 432 shownin FIG. 11.

It is to be noted that the block or strap members 434A and 4343 assistin preventing lateral movement of the leads 86 and 84 with respect toeach other, such as might otherwise occur during certain abnormaloperating conditions when heavy overload currents are flowing throughsaid leads which would then tend to move away from each other laterallyand change the spacing between said leads and the pick-up coil 62 of thethermally responsive device 50. In addition, a compression or biasingspring 435 is disposed in a recess 431 of the strap or block member43413 to bear against one of the feet 342 of the thermally responsivedevice 50 to thereby cause the main portion 44 of the base member 40 ofsaid device to bear against the'leads 86 and 84 of the transformer 10even during abnormal operating conditions of said transformer, such aswhen heavy overload currents are flowing in the leads 86 and 84, whensaid leads might otherwise tend to deform and cause a separation orchange in the spacing between said leads and the pick-up coil 62 of thethermally responsive device 50 intermediate the clamping means 430 whichare disposed at the ends of said thermally responsive device.

In summary, the mounting arrangement just described tends to maintainsubstantially a predetermined desired spaced relationship between thepick-up coil 62 of the thermally responsive device 50 and the adjacentleads 86 and 84 of the transformer 10. As mentioned previously, thelatter arrangement is important to maintain substantially a uniformelectromagnetical coupling between the current in the leads 86 and 84 ofthe transformer 10 and the device 50 during substantially all operatingconditions of said transformer.

In the operation of the thermally responsive means 50, as thetemperature or thermal condition of the transformer it) graduallyincreases, the free end of the bimetallic member 64 deflects in anupward direction until said free end forms a closed circuit with thestationary contact member 63 between the upper end of the looselycoupled coil 45 at the terminal 77 and the conductor 288 in thesignalling means through the terminal 59 for reasons which will bediscussed hereinafter. As the temperature or thermal condition of thetransformer 10 increases still further and reaches substantially asecond predetermined operating or thermal condition, the free end of thebimetallic member 66 deflects in an upward direction until said free endforms a closed circuit with the stationary contact member 65 whichextends from the upper end of the loosely coupled coil 45 at theterminal 77 through the operating coil 152 of the tripping solenoid andto the lower end of the loosely coupled coil 45 at the terminal 75, thusenergizing the operating coil 152 of the tripping solenoid 150. Byconnecting the operating coil 152 of the tripping solenoid 150 acrossthe loosely coupled coil 45 and energizing said operating coil, thebimetallic member 66 of the thermally responsive means 50 actuates thecontact members 122 and 128 of the circuit breaker to circuitinterrupting positions, as previously described for said circuitbreaker, in response to a predetermined operating or thermal conditionof the transformer 10, thus interrupting the connection between thesecondary leads 82 and 88 and the associated distribution circuitterminals 22 and 28, respectively, and interrupting current flow in thesecondary winding portions 42A and 42B of the transformer 10 to protectsaid transformer from damage which might result from further loading oroverloading. It is important to note that the thermally responsive means50 protects the transformer 10 by actuating the circuit breaker 100 to acircuit interrupting position in responseto gradually increasing andprolonged operating or load conditions of a moderate de gree and inresponse to excessive overload conditions of 'a short time nature, suchas those resulting from a short circuit condition at the distributioncircuit conductors or terminals 22, 24, 26 and 28. It is also importantto note that the thermally responsive means 50 is responsive to the sumof the load currents flowing in the secondary leads 84 and 86 and in theassociated secondary winding portions 42A and 42B of the transformerllll and therefore to the total thermal condition of said transformer.

Referring again to FIG. 2, the signalling means 116' comprises anindicating lamp 78, which, in general is energized by the operation ofthe thermally responsive means Sil to indicate that a firstpredetermined operating or thermal condition of the transformer 10 hasbeen eached and a latching or holding relay 7b which maintains theenergization of said indicating lamp after the indicating lamp has beenenergized by the thermally responsive means 50.

In particular, one end of the indicating lamp '78 is connected by theconductor 286 to the lower end of the coil portion 45A of the looselycoupled coil 45 at the tap connection or terminal 287. The other end ofthe indicating lamp 78 is connected by the conductor 288 to the terminal59 which is connected in turn to the stationary con-tact member 63 ofthe thermally responsive means 50 through the conductor 04. The latchingor holding relay 76) comprises an operating coil '74 and a holdingcontact 76 which is normally open when said operating coil isdeenergized. The operating coil 74 of the holding relay 7th is connectedin parallel circuit relationship with the indicating lamp '78 bet-weenthe conductor 286 and the conductor 288, which is connected to theterminal 59. The holding contact 76 of the holding relay 70 is connectedin series circuit relationship with the parallel circuit which includesthe operating coil 74 and the indicating lamp 78, the series circuitbeing connected between the terminal 287 and the terminal 216 of themanually operable means 210. When the manually operable means are is inthe neutral position as shown in FIG. 2, the terminal 216 is connectedin turn by the bridging contact member 213 to the terminal 218 which isconnected in turn to the terminal 77 and to the upper end of the coilportion 45A of the loosely coupled coil 45 to permit energization of theindicating lamp 78 by the operation of the bimetallic member 64 of thethermally responsive means 50.

In the operation of the signalling means 11%, assuming that the manuallyoperable means 213 is in the neutral position shown in FIG. 2, as thetemperature or thermal condition of the transformer it graduallyincreases to a predetermined operating or thermal condition, thebimetallic member 64 of the thermally responsive means will move upwardand form with the stationary contact member 63 a closed circuit whichextends from the terminal 287 at the lower end of the coil portion 45Aof the loosely coupled coil 45 through the conductor 286, the indicatinglamp 78, the conductor 2855, the terminal 5%, the contact member 63, thebimetallic member 64, the terminal 77 to the upper end of the coilportion 45A thus connecting the coil portion 45A across the indicatinglamp 7? and energizing said indicating lamp, which is visible exteriorlyof the casing 46, as best shown in FIG. 5, to signal or indicate thatsaid predetermined operating or thermal condition of the transformer it?has been reached. The energization of the indicating lamp 7% by thethermally responsive means 59 also energizes the operating coil 74 ofthe holding relay 7d which is connected in parallel with said indicatinglamp to thereby actuate the normally opened contact 76 of said holdingrelay to a closed position thus forming a holding circuit which extendsfrom the terminal 287 at the lower end of the coil portion 45A, throughthe indicating lamp 73, the contact in, the terminal 216 of the manuallyoperable means Elli, the bridging contact member 213 and the terminal2E3 of said manually operable means to the terminal 7'7 and the upperend of the coil portion 45A of the loosely coupled coil 4-5. The latteroperation, therefore, maintains the energization of the signalling lamp'78 after said lamp has been once energized by the operation of thebimetallic member 64 of the thermally responsive Cir means :Ttlindependently of the deflection of the bimetallic member 64 until thesignalling means lid is reset by operation of the manually operablemeans Elli, as will be discussed hereinafter. In other words, theindicating lamp 7% of the signalling means 11%) remains energized afterbeing energized by the operation of the bimetallic member d4 of thethermally responsive means 5d, even though the bimetallic member 54should subsequently change its deflection to a circuit interruptingposition with respect to the contact member 53, as the transformer it?cools and the tel lpcrature or thermal condition of said transformerdecreases below said predetermined operating or thermal condition.

It is also important to note that the indicating lamp 73 of thesignalling means ll'tl may also be energized by the operation of theauxiliary contact member 134 of the circuit breaker 1% whenever thecontact members 122 and 128 of said circuit breaker are actuated to acircuit interrupting position by either the thermally responsive means5d or the manually operable means 22%. In particular, whencver thecontact members 122 and 128 of the circuit breaker it'll} are actuatedto circuit interrupting positions, the auxiliary contact member 134 isactuated to a closed position thus forming a closed circuit whichextends from the upper end of the coil portion 45A at the terminal '77,through the contact member 134 to the erminal 59 and the indicating lamp73, through the conductor 283 and to the lower end of the coil portion455A at the terminal 287 through the conductor 2-86, thus energizing theindicating lamp 73. The contact member 134-, therefore, operates also toverify the reclosing operation of the circuit breaker 1% by the manuallyoperable means 21E) since the indicating lamp '78 of the signallingmeans ill) will remain energized by the contact member 134 so long asthe contact members 122 and 1255 of the circuit breaker 1% are in thecircuit interrupting positions but will deenergize said indicating lampwhen the contact members 122 and 128 or" said circuit breaker areactuated to a closed position by the operation of the manually operablemeans 219. In addition, if the bimetallic member 64 of the thermallyresponsive means 59 should fail to energize the indicating lamp 7% uponthe reaching of the first predetermined operating condition, then thecontact member 134 will operate to energize said indicating lamp uponthe reaching of the second predetermined operating condition when thecircuit breaker ldil is actuated to a circuit interrupting position bythe thermally responsive means 59.

Referring now to FIGS. 1 through 5, the manually operable means 210 isprovided for actuating the circuit breaker 1% to circuit interruptingand circuit closing positions independently of the operation of thethermally responsive means 5%) and for resetting the signalling means11% after said signalling means has been once energized by the operationof said thermally responsive means. In other words, the manuallyoperable means 21%) is connected in circuit relation with the circuitbreaker ltltl for connecting the electrically operated tripping means orthe electrically operated reclosing means Mil to the loosely coupledcoil 25' and in circuit relation with the signalling means lid fordeenergizing and resetting said signalling means after said signallingmeans has been once energized by the thermally responsive means 58.

More particularly, the manually operable means 210 comprises anoperating handle which is available or accessible exteriorly of thecasing 46 of the transformer 10 and which may be actuated to a pluralityof positions and a switching means which is mechanically coupled to saidoperating handle and disposed internally of said casing for changing theconnections of the loosely coupled coil 45 to the signalling means Hilland to the electrically operated trippin means and reclosing means 154)and 140, respectively, of the circuit breaker 100.

As best shown in FIGS. 1 and 5, the manually operable means or device21% includes a foundation or base 13 portion 248 having an outwardlyflaring skirt 263, an inner recess 246 and a rearwardly extending sleeveportion 272. The stem or sleeve portion 272 is arranged to extendinwardly through an opening in the wall of the casing 46. As describedin U.S. Patent 2,356,055 filed by J. K. Hodnette et al. and assigned tothe same assignee as the present application for a similar switchemployed to mechanically actuate an associated circuit interrupter, thesleeve portion 272 may be provided with a plurality of slots (not shown)into which associated fingers (not shown) in the walls of the casing 45extend to position the sleeve or base portion of the overall structureso as to prevent said sleeve or base portion from rotating about itsaxis. The base or quadrant portion 248 is held tightly against the wallof the casing 46 by a nut 26-6 on the inner side thereof which pullssaid base portion inwardly to apply pressure to a gasket 262 positionedbetween the casing 46 and a shoulder of the base portion 248. The nut266 is arranged to engage a threaded portion 265 of the base or quadrantportion 248. The manually operable means or device 216) also includes ahandle portion comprising the handle 232 and a body 231 integrallyformed therewith and extending within the recess or cavity 246 of thebase or quadrant portion 248. The handle 232 includes a recess or hole242 to accommodate a hook stick which may be employed to rotate saidhandle and actuate the manual operable means 2% to a new position, Asleeve or internally hollow operating shaft 274 is attached or securedby suitable means, such as welding or soldering, at 26E) to the body 231and extends inwardly beyond the sleeve 272 of the base or quadrantportion 248. The handle 232 together with the integral body 231 and thesleeve or operating shaft 274 comprise arotatable member which isconcentrically arranged with respect to the stationary base or quadrantportion 248. A crank arm or lever member 224 is secured to the inner endof the sleeve 2'74 by any suitable means so that said lever member movesor rotates about the axis of said sleeve upon operation or rotation ofthe handle 232. For example, as disclosed in U.S. Patent 2,356,055previously mentioned for a similar device, a plurality of slots (notshown) may be provided on the inner end of the sleeve 274 into whichfingers (not shown) of the lever member 224 extend. A retaining ring 228is disposed in a slotted portion 276 of the inner end of the sleeve 274to retain the lever member 224 in position.

The indicating lamp 78 may be mounted in a socket formed by the sleeveor operating shaft 27 by means of projections (not shown) extending intoslots in the sleeve 274 in a well-known manner and bringing the lampcontact members 2755 into engagement with contact members 282 heldwithin a block 284 of insulating material and connected to the circuitconductors 236 and 288. An O-ring type gasket or packing member 264 isprovided in a slotted portion 247 of the base or quadrant portion 243adjacent to the outside surface of the sleeve 274 to assist inpreventing the entrance of moisture into the casing 46 of thetransformer 16.

Referring to FIGS. 4 and 5, a covering or guard 256, having asubstantially spherically outer portion, is attached by suitablefastening means, such as a screw (not shown) clamping action, or by asuitable bonding material, to the body 231 of the handle portion of themanually operable means 210. An opening is provided in the forward lowerpart of the cover or guard 256 for retaining a glass crystal or jewel253 that is preferably colored red to provide a danger signal upon ttheoverheating of the transformer 16, as indicated by'the energization ofthe indicating lamp 7%. A gasket member 254 is disposed between theinner end of the glass crystal or jewel 258 and the body 231 of thehandle portion of the manually operable means 219 to assist inpreventing the entrance of moisture into the casing 45 of thetransformer 10. A position indicating or dial member 252 14 is attachedor secured to the flared portion263 of the base or quadrant portion 248or may be formed integral-, ly therewith. A projection 257 is providedon the guard member 256 which rotates with the handle 232 to indicatethe position of the manually operable means 21% as marked on theposition indicating member 252.

Referring to FIGS. 2 and 3, the lever member 224 is actuated in generalby the rotation of the handle 232 externally of the casing 46 tomanually operate the switching means 22% internally of said casing bymeans of a connecting rod 238 to one of a plurality of positions. Inparticular, a lost motion connection 225 is provided between the levermember or crank arm 224 and the connecting rod 238 by means of a slot orrecess 226 in the crank arm 224 and the upper end of said connecting rodwhich is turned into said slot and held captive by suitable means suchas a washer and cotter pin (not shown). The lost motion connection 225is provided in order that the rotational travel of the crank arm orlever member 224 be similar to or substantially coincide with that of aconventional operating handle in a switch operator,

such as disclosed in U.S. Patent 2,356,055 previously mentioned. Thelower end of the connecting rod 238 is pivotally connected to therotatable switch arm 212 of the switching means 222 by means of a pivotpin 292.

The switching means 220 comprises a rotatable switch arm 212 formed froma suitable insulating material, a movable bridging contact member 213which isfixedly attached or fastened to said switch arm and a pluralityof finger type stationary contact members 214, 216, 218 and 222. Therotatable switch arm 212 is pivotally mounted by means of a pivot pin215 which is supported in turn by the bracket member 296, asbest shownin FIGS. 1 and 3. The switch arm 212 is arranged to rotate about thepivot pin 215 when actuated by the vertical movement of the connectingrod 233. The movable bridging contact member 213 is rigidly connected tothe switch arm 212 by suitable fastening means, such as the rivets 217,and arranged to rotate with said switch arm. The stationary contactmembers214, 216, 213 and 222 are mounted or supported on anarcuately-shaped terminal supporting or bracket member 294 to which saidstationary contact members are fastened by suitable means, such asrivets or screws, the upper end of each of said terminals being arrangedto be engaged by the movable bridging contact member 213 as said movablecontact member rotates with the switch arm 212. Th terminal supportingmember 224 is mounted on or supported in turn by the bracket member 2%to which said terminal supporting member is fastened by suitable means,such as rivets or bolts. As best shown in FIG. 1, the bracket member 2%is secured to the inner side of the casing 56 by suitable means, such asthe nut 266 or by welding, and includes a recess throughwhich passes thesleeve or internally hollow operating shaft 274 of the manually operablemeans 210. It should be noted that the holding relay '76 of thesignalling means 116 may be physically mounted on or supported by thebracket member 2%, as best shown in FIG. 3.

In order to maintain the switching means 220 in the neutral positionwith the movable bridging contact member 213 electrically connecting thestationary contact members or terminals 216 and 218, as shown in FIG. 3,and in order to permit the energization of the signalling means 11h bythe thermally responsive means 50, the connecting rod 238 is providedwith a flange member 244 which is mounted thereon or formed integrallytherewith. The opposing compression or bias springs 236 are thenprovided on the opposite sides of the flange member 244 and restrainedby the projecting members or abutments 297 of the bracket member 2%. Theprojecting members or lugs 297 of the bracket member 2% are formed withthe recesses or apertures through which pass the connecting rod 238 topermit vertical movement of said connecting rod while restraining thecompression 15 springs 235. The compression springs 236 bear against orapply pressure to the opposite sides of the flange member 244 tomaintain the connecting rod 233, as well as the switching means 226, inthe neutral position shown in FIG. 3.

As previously mentioned, the switching means 22 of the manually operablemeans 216 is connected in circuit relation'with both the circut breakertrill and the signalling means lltl. In particular, the stationarycontact member 214 of the switching means 220 is connected to one sideof the normally closed contact 156 of the tripping solenoid 159 which isconnected in series circuit relation with the operating coil 142 of thereclosing solenoid 140. The stationary contact member 216 of theswitching means 220 is connected to one side of the holding contact 76of the holding relay 7b in the signalling means 110, said holdingcontact being connected in series circuit relation with both theindicating lamp 78 and the operating coil 74 of the holding relay 7t).The stationary contact member 213 of the switching means 229, which maybe considered as a common terminal of the switching means 226 since itis engaged by the movable bridging contact member 213 in all positionsof said switching means, is connected to the upper end of the looselycoupled coil portion 4 5A. The stationary contact member 222 of theswitching means 220 is connected to the upper end of the operating coil152 of the tripping solenoid 15411.

The operation of the manually operable means Zlil in actuating theoperation of the circuit breaker rec independently of the operation ofthe thermally responsive means 50 and in resetting the signalling means119 after said signalling means has been activated by the operation ofsaid thermally responsive means will now be described. In the neutralposition in which the manually operable means 210 and more particularly,the switching means 229 is maintained, with the movable bridging contactmember 213 electrically connecting the stationary contact members 216and 218 as shown in FIG. 2, the signalling means lltl may be energizedby the thermally responsive means 50 and more particularly by thebimetallic member M as previously described.

It the signalling means llltl has been energized by the operation of thebimetallic member 64 of the thermally responsive means 59, as previouslydescribed, and said energization is being maintained by the holdingrelay 7% of said signalling means, the manually operable means Zlt) maybe manually operated to reset said signalling means assuming that thethermal condition of the transformer 10 has changed and the free end ofthe bimetallic member 64 of the thermally responsive means Si no longerforms a closed circuit with the stationary contact member 63 of saidthermally responsive means and that the circuit breaker is in a circuitclosing position with the contact member 134 in the open position. Toreset the signalling means 11%, the operating handle 232 is rotated oractuated in the counterclockwise direction by suitable means, such as ahook stick, with the projection 257 on the guard member 256 moving inthe direction of the arrow above the word LIGHT on the positionindicating member or dial member 252 of said manually operable means.The latter motion is transmitted from the operating handle through thesleeve or operating shaft 274, the crank arm 224 and the connecting rod238 to the switch arm 212 01 the switching means 22%. When theprojection 257 on the guard member 256 moves sufficiently in thedirection of the arrow above the Word LIGHT on the position indicatingmember 252, the movable bridging contact member 213 of the switchingmeans 226 no longer engages the stationary Contact member 216, thusdisconnecting the upper end of the loosely coupled coil 45 from theholding contact '76 of the holding relay 7% and deenergizing saidholding relay, as well as the indicating lamp 7?). It is to be notedthat the direction of the rotation of the switch arm 212 is in aclockwise direction or opposite to the counterclockwise direction ofrotation of the operating handle 232 in the diagrammatic view shown inFIG. 2.

in order for the nlanually operable means 210 to actuate the circuitbreaker Wil to a circuit interrupting position, the operating handle 232of said manually operable means is actuated or rotated in a clockwisedirection, as shown in 4, with the projection 257 011 the guard member5256 moving in the direction of the arrow above the word OPEN marked onthe dial member 252. When the projection 257 on the guard member 256moves in the direction of the arrow above the word OPEN andsubstantially lines up with the word ()PEN, contact member 213 of theswitching means 226 is rotated in a counterclockwise direction until thestationary contact member 2R8 is electrically connected to thestationary contact member 222, thus connecting the upper end of theoperating coil i521 of the trippin solenoid 15%) to the upper end of theloosely coupled coil 45 and energizing said operating coil, since thelower end of said operating coil is already connected to the lower endof the loosely coupled coil 45 at the terminal '75, as well as actuatingthe circuit bre ker 1% to a circuit interrupting position as previouslydescribed for the energized condition of said operating coil. It is tobe noted that the latter actuation of the ci cuit breaker Edit to acircuit interrupting position by the manually operable means 21% may beaccomplished independently of the operation of the thermally responsivemeans 5%.

in order for the manually operable means 219 to actuate the circuitbreaker litltl to a circuit closing position, the operating handle 232of said manually operable means is actuated or rotated in acounterclockwise direction with the projection 257 on the guard member256 moving in the direction of the arrow above the word CLOSE on theposition indicating member 252, as shown in FIG. 4. When the projection257 on the guard member 256 substantially lines up with the word CLOSEon the dial member 252. the switch arm 212 of the switching means 22%)is rotated in a clockwise direction, as shown in FIG. 2, until thebridging member 213 electrically connects the stationary contact member214 and the stationary contact member 213, thus connecting the upper endof the loosely coupled coil to the right end of the operating coil 142of the reclosing solenoid Mt) through the normally closed contact 156 ofthe tripping solenoid 150 and energizing said reclosing solenoid sincethe other end of said operating coil is connected to the lower end ofthe loosely coupled coil at the terminal energizing the operating coil14-2 of the reclosing solenoid lid-t9 operates to actuate the circuitbreaker lltltl to a circuit closing position, as previously described.If the tripping solenoid is being energized by the operation of thethermally responsive means 53', the manually operable means 211i) cannotactuate the circuit breaker ltltl to a circuit closing position sincethe norm: lly closed contact 156 of the trip solenoid lEh will be open,thus providing trip free operation of the circuit breaker 1%. Aspreviously mentioned, the reclosing operation of the circuit breakerliltl by the operation of the manually operable means Zltl is verifiedby the operation of the contact member 134 of the circuit breaker tilt)which will remain closed, unless the associated contact members 122 and128 of said circuit breaker are in the circuit closing position, andenergize the indicating lamp 7% of the signalling means 11% until thecircuit breaker tilt? is actuated to a circuit closing poistion by theoperation of the manually operable means Zlltl. It is to be noted thatthe manually operable means 210, including the switching means 229, isalways returned to the neutral position shown in FIGS. 2 and 3 by theoperation of the compression springs 236 and the flange member 244unless the operating handle 232 of said manually operable means is beingactuated either in a clockwise or counterclockwise direction by asuitable means, such as a hook stick. It is also to be noted that thestationary contact members 214, 21 and 222 may be protected by asuitable guard member or cover 295 in certain applications, as shown inFIG. 3.

Referring to FIG. 6, there is illustrated an alternate manually operablemeans 210 including an alternate dial or position indicating member 256and with the stationary contact member 216' mounted between thestationary contact members 214 and 218, as shown in phantom in FIG. 3.The manually operable means 210' is otherwise the same as the manuallyoperable means 210 and the electrical connections are the same as forthe manually operable means 210.

In general, the operation of the manually operable means 216' is similarto that of the manually operable means 210 except that to reset thesignalling means 119 the operating handle 232' is rotated in a clockwisedirection and the switch arm 212 in a counterclockwise direction towardthe terminal or contact member 222 thus interrupting the connectionbetween the common terminal 218 and the terminal 216 in the newposition. The former arrangement of the manually operable means 210previously decsribed in detail, has the advantages that overtravel ofthe operating handle 232, shown in FIG. 4, and the switch arm 212 cannotinadvertently energize the tripping solenoid 150 and also that it is notnecessary to reset the signalling circuit 110 after the manual operablemeans 210 has actuated the circuit breaker 100 to a circuit closingposition.

In particular, if the signalling means 110 has been energized by theoperation of the bimetallic member 64 of the thermally responsive means56, as previously described, and said energization is being maintainedby the holding relay 79 of said signalling means, the manually operablemeans 210' may be manually operated to reset said signalling meansassuming that the thermal condition of the transformer has changed andthe free end of the bimetallic member 64 of the thermally responsivemeans 50 no longer forms a closed circuit with the stationary contactmember 63 of said thermally responsive means and the circuit breaker 100is in a circuit closing position with the contact member 134 in the openposition. To reset the signalling means 110, the operating handle 232 isrotated or actuated in the clockwise direction by suitable means, such ahook stick until the projection 257' on the guard member 255'substantially lines up with the arrow marked LIGHT on the positionindicating member or dial member 252' of said manually operable means.The latter motion is transmitted from the operating handle through thesleeve or operating shaft 274, the crank arm 224 and the connecting rod238 to the switch arm 212 of the switching means 220. When theprojection 257 on the guard member 256' substantially lines up with thearrow marked LIGHT on the position indicating member 252', the movablebridging contact member 213 of the switching means 220 no longer engagesthe stationary contact member 216' and does not yet engage thestationary contact member 222, thus disconnecting the upper end of theloosely coupled coil 45 from the holding contact 76 of the holding relay70 and deenergizing said holding relay, as well as the indicating lamp 73. It is to be noted that the direction of the rotation of the switcharm 212 is also in a counterclockwise direction or opposite to theclockwise direction of rotation of the operating handle 232' in thediagrammatic view shown in FIG. 2.

In order for the manually operable means 210' to actuate the circuitbreaker 10! to a circuit interrupting position, the operating handle 232of said manually operable means is actuated or rotated further in aclockwise direction as shown in FIG. 6 until the projection 257' on theguard member 256' substantially lines up with the arrow marked OPEN.When the projection 257 on the guard member 256' substantially lines upwith the arrow OPEN, the bridging contact member 213 of the switchingmeans 22A; is rotated in a counterclockwise direction until thestationary contact member 213 is electrically connected to thestationary contact member 222, thus connecting the upper end of theoperating coil 152 of the tripping solenoid 150 to the upper end of theloosely coupled coil 45 and energizing said operating coil since thelower end of said operating coil is already connected to the lower endof the loosely coupled coil 45 at the terminal 75, as well as actuatingthe circuit breaker 1% to a circuit interrupting position as previouslydescribed for the energized condition of said operating coil. It is tobe noted that the latter actuation of the circuit breaker 10!) to acircuit interrupting position by the manually operable means 210' mayalso be accomplished independently of the operation of the thermallyresponsive means Stl.

In order for the manually operable means 210' to actuate the circuitbreaker 160 to a circuit closing position, the operating handle 232' ofsaid manually operable, means is actuated or rotated in acounterclockwise direction until the projection 257 on the guard member256' substantially lines up with the arrow marked CLGSE on the positionindicating member 252 as shown in FIG. 6. When the projection 257' onthe guard member 256' substantially lines up with the arrow markedCLOSE, the switch arm 212 of the switching means 220 is rotated in aclockwise direction, as shown in FEG. 2, until the bridging member 213electrically connects the stationary contact member 214 and thestationary contact member 218, thus connecting the upper end of theloosely coupled coil to the right end of the operating coil 142 of thereclosing solenoid 140 through the normally closed contact 156 of thetripping solenoid 150 and energizing said reclosing solenoid since theother end of said operating coil is connected to the lower end of theloosely coupled coil 45 at the terminal 75. Energization of theoperating coil 142 of the reclosing solenoid 14!) operates to actuatethe circuit breaker to a circuit closing position as previouslydescribed. It the tripping solenoid 150 is being energized by theoperation of the thermally responsive means 50, the manually operablemeans 210 cannot actuate the circuit breaker 108 to a circuit closingposition since the normally closed contact 156 of the trip solenoid 150will be open, thus providing trip free operation of the circuit breaker100. As previously mentioned, the reclosing operation of the circuitbreaker 1% by the operation of the manually operable means 210 isverified by the operation of the contact member 134 of the circuitbreaker 100 which will remain closed unless the associated contactmembers 122 and 128 of said circuit breaker are in the circuit closingposition and energize the indicating lamp 78 of the signalling meansuntil the circuit breaker 100 is actuated to a circuit closing positionby the operation of the manually operable means 210'. It is to be notedthat the manually operable means 210', including the switching means220, is always returned to the neutral position shown in FIGS. 2 and 3by the operation of the compression springs 236 and the flange member244 unless the operating handle 232' of said manually operable means isbeing actuated either in a clockwise or counter clockwise direction by asuitable means, such as a hook stick. It is also to be noted that thestationary contact members 214, 216, 218 and 222 may be protected by asuitable guard member or cover 295 in certain applications, as shown inFIG. 3.

It is to be understood that in certain applications, the 7 of theoperating handle 232, the crank arm 224 and the switch arm 212 of saidmanually operable means. It is also to be understood that in aprotective system as disclosed, the circuit breaker 1% may be providedwith automatic reclosing means, as an alternative to the manuallyoperable reclosing means included in the manually operable means 21% or219 or in combination with said manually operable means in a particularapplication. it is also obvious that an electrical transformer asdisclosed may be provided in a polyphase or three-phase embodimentrather than being a singlephase unit as illustrated in FIGS. 1 through5. Since the circuit interrupter or circuit breaker included with anelectrical transformer as disclosed may include both electricallyoperated tripping means and electrically operated reclosing means, themanually operable means 21%) or 216 may be provided at a remote locationrather than being mounted directly on the casing 46 and internally ofsaid casing as disclosed.

The apparatus embodying the teachings of this invention has severaladvantages. For example, electrical energy required for the operation ofthe signalling means or circuit and the circuit breaker which mayinclude both electrically operated tripping and reclosing means in atransformer as disclosed is assured, so long as one of the main windingsof said transformer is connected to a source of electrical currentwithout subjecting said signalling means or said electrically operatedtripping or reclosing means to dangerous over-voltages when a surgevoltage is present on one of said main windings. In addition, atransformer as disclosed is protected automatically from dangerousoverload conditions, as previously described, in response to a thermallyresponsive means while certain mechanical problems are substantiallyeliminated in interrupting load currents of a transformer as dis closedparticularly for higher ratings of said transformer. Since numerouschanges may be made in the above described apparatus and circuits anddifferent embodiments of the invention may be made without departingfrom the spirit and scope thereof, it is intended that all the mattercontained in the foregoing description or shown in the accompanyingdrawing shall be interpreted as illustrative and not in a limitingsense.

We claim as our invention:

' 1. A protected transformer comprising an insulated high voltagewinding, an insulated low voltage winding, a casing, a fluid dielectricin said casing, said windings being disposed in said dielectric, leadsconnected to said low voltage winding and passing out of said casing, areclosable circuit interrupter disposed within said casing and havingcontacts in series circuit relation with at least one of said leads,said interrupter including electrically operated tripping means foropening said contacts when energized, a coil loosely coupled ininductive relation with said high voltage winding for supplying electriccurrent, first individually adjustable thermally responsive means forconnecting said coil to said tripping means to open said contacts inresponse to a predetermined temperature condition of said fluiddielectric, a signalling means, and second individually adjustablethermally responsive means operable independently of the first thermallyresponsive means for connecting said signalling means to said coil toenergize said signalling means in responsise to a lower temperaturecondition of said fluid dielectric.

2. A protected transformer comprising an insulated high casing, a fluiddielectric in said casing, said windings being disposed in saiddielectric leads connected to said low being disposed in said dielectricleads connected to said voltage winding and passing out of said casing,a reclosable circuit interrupter disposed within said casing and havingcontacts in series circuit relation with at least one of said leads,said interrupter including electrically operated tripping means foropening said contacts when energized, electrically operated means forreclosing the contacts of said interrupter, a coil loosely coupled ininductive relation with said high voltage winding for supplying electriccurrent, first individua ly adjustable thermally responsive means forconnecting said coil to said tripping means to open said contacts inresponse to a preleterinined temperature condition of said dielectric, aignalling means, second individually adjustable thermally responsivemeans, operable independently of said first thermally responsive meansfor connecting said signalling means to said coil to energize saidsignalling means in response to a diiferent tem perature condition ofsaid dielectric, and means for connecting said reclosing means to saidcoil to energize said reclosing means and close the contacts of saidinterrupter only when said tripping means is deenergized.

3. A transformer comprising an insulated high voltage Winding, aninsulated low voltage winding, a casing, a fluid dielectric in saidcasing, said windings being disposed in said dielectric, leads connectedto said low voltage winding and passing out of said casing, a reclosablecircuit interrupter disposed within said casing and having contacts inseries circuit relation with at least one of said leads, saidinterrupter including electrically opera-ted trip ping means for openingsaid cont-acts when energized, a coil loosely coupled in inductiverelation with said high voltage winding for supplying electric current,first individually adjustable thermally responsive means for conncctingsaid coil to said tripping means to open said contacts in response to apredetermined temperature condition of said fluid dielectric, asignalling mean-s, second individually adjustable thermally responsivemeans operable independently of the first thermally responsive means forconnecting said signalling means to said coil to energize saidsignalling means in response to a lower temperature condition of saidfluid dielectric, and switching means actuated by said interrupter forconnecting said coil to said signalling means when said contacts of saidinterrupter are in the open position.

4. A protected transformer comprising an insulated high voltage winding,insulated low voltage windings, a casing, a fluid dielectric in contactwith said windings in said casing, leads connected to said low voltagewindings and passing out of said casing, a reclosable circuitinterrupter disposed Within said casing and havin contacts in seriescircuit relation with at least one of said leads, said interrupterincluding electrically operated tripping means for opening said contactswhen energized, a coil loosely coupled in inductive relation with saidhigh voltage winding for supplying electric current, first thermallyresponsive means for connecting said coil to said tripping means to opensaid contacts in response to a predetermined temerature condition ofsaid dielectric, a signalling means, second thermally responsive meansfor connecting said signalling means to said coil to energize saidsignalling means in response to a lower temperature condition of saiddielectric, relay means for maintaining said signalling means in theenergized condition after said second then mally responsive meansconnects said coil to said signalling means independently of thecondition of said second thermally responsive means, and manuallyoperable means for resetting said relay means without affecting theoperation of the circuit interrupter.

5. A transformer comprising an insulated high voltage winding, aninsulated low voltage winding, a casing, a fluid dielectric in contactwith said windings in said casing, leads connected to said low voltagewinding and passing out of said casing, a reclosable circuit interrupterdisposed within said casing and having contacts in series circuitrelation with at least one of said leads, said interrupter includingelectrically operated tripping means for opening said contacts whenenergized, a coil loosely coupled in inductive relation with said highvoltage winding for supplying electric current, first thermallyresponsive means for connecting said coil to said tripping means to opensaid contacts in response to a predetermined temperature condition ofsaid fluid dielectric, a signalling means, second thermally responsivemeans for connecting said signalling means to said coil to energize saidsignalling means in response to a lower temperature condition of saidfluid dielectric, and means for resetting said signalling means to thedeene-rgized condition without opening said contacts when said secondthermally responsive means is not connecting said coil to saidsignalling means.

6. A transformer comprising windings subject to varying load,electrically energized signalling means for indicating a predeterminedload on said transformer, a circuit breaker including electricallyoperated tripping and reclosing means connected in circuit relation withsaid windings to disconnect the windings from said load, a casing forsaid transformer, a coil loosely coupled electromagnetically with saidwindings for supplying electric current, load responsive means forselectively connecting said coil to said signalling and said trippingmeans to energize said means, relay means for maintaining saidsignalling means energized independently of said load responsive means,manually operable means for actuating said breaker to an open positionand to a closed position and for resetting said relay means withoutaffecting the operation of the circuit breaker, said manually operablemeans comprising a stationary base portion mounted on said casing, ahandle portion concentrically arranged on said base portion, switchingmeans mechanically coupled to said handle portion for changing theconnections between said coil and said tripping, reclosing andsignalling means at diiferent positions of said handle portion to changethe energization of said latter means, and biasing means for maintainingsaid switching means in a neutral position, said switching means beingconnected in circuit relation with said coil when the switching means isin the neutral position to permit the energization of said tripping andsignalling means by said load responsive means.

7. A transformer comprising a core, a primary Winding on said core, asecondary winding on said core and comprising two coils each having apair of leads extending therefrom, three secondary terminals, one leadfrom each of the two coils being each connected to a common one of saidterminals, said leads having current flowing therethroughinstantaneously in opposite directions, the other lead from each of thetwo coils being each connected to an individual one of said terminals, amutipole circuit breaker having contacts for opening the circuitsthrough the two leads connected to the individual terminals, a pickupcoil inductively responsive to the sum of the currents flowing in bothof the two leads connected to the common terminal, control meansconnected to be atiected by the current in said pick-up coil andconnected to cause tripping operation of said circuit breaker.

8. A transformer comprising a core, a primary Winding on said core, asecondary winding on said core and comprising two coils each having apair of leads extending therefrom, at least two of said leads each froma difierent one of said coils being substantially rigid conductors inwhich current flows instantaneously in opposite directions, a pick-upcoil mounted on both of said substantially rigid conductors and mutuallycoupled therewith to produce an output current varying with the sum ofthe currents flowing in said two conductors, a circuit breaker havingcontacts serially connected in each of the other two leads from the twosecondary coils, and control means responsive to the current in saidpick-up coil and electrically connected to cause opening of the contactsof said circuit breaker in the other two leads from the two secondarycoils.

9. A transformer comprising a casing, windings disposed in said casing,leads extending out from one of said windings through said casing, saidleads comprising at least two conductors in which current fiowsinstantaneously in opposite directions, a current pick-up coil disposedadjacent to and non-ferromagnetically coupled to said two conductors forobtaining an output current which varies in a substantially linearmanner with the sum of the currents in said two conductors, the plane ofsaid coil being substantially parallel to the plane of said conductors,thermally responsive devices connected in series circuit realtion withsaid coil to be heated by the output current thereof, and control meanscontrolled by the operation of said thermally responsive devices.

References Cited by the Examiner UNITED STATES PATENTS 2,298,229 10/ 42Putman 317-14 2,333,537 1 1/43 Leonard 317- 14 2,356,055 8/44 Hodnett317-14 2,597,185 5/52 Roeding a- 317-44 2,650,356 8/53 Stein 317153,126,500 3/64 Astleford et al 3l7-14 MAX L. LEVY, Primary Examiner.

1. A PROTECTED TRANSFORMER COMPRISING AN INSULATED HIGH VOLTAGE WINDING,AN INSULATED LOW VOLTAGE WINDING, A CASING, A FLUID DIELECTRIC IN SAIDCASING, SAID WINDINGS BEING DISPOSED IN SAID DIELECTRIC, LEADS CONNECTEDTO SAID LOW VOLTAGE WINDING AND PASSING OUT OF SAID CASING, A RECLOSABLECIRCUIT INTERRUPTER DISPOSED WITHIN SAID CASING AND HAVING CONTACTS INSERIES CIRCUIT RELATION WITH AT LEAST ONE OF SAID LEADS, SAIDINTERRUPTER INCLUDING ELECTRICALLY OPERATED TRIPPING MEANS FOR OPENINGSAID CONTACTS WHEN ENERGIZED, A COIL LOOSELY COUPLED IN INDUCTIVERELATION WITH SAID HIGH VOLTAGE WINDING FOR SUPPLYING ELECTRIC CURRENT,FIRST INDIVIDUALLY ADJUSTABLE THERMALLY RESPONSIVE MEANS FOR CONNECTINGSAID COIL TO SID TRIPPING MEANS TO OPEN SAID CONTACTS IN RESPONSE TO APREDETERMINED TEMPERATURE CONDITION OF SAID FLUID DIELECTRIC, ASIGNALLING MEANS, AND SECOND INDIVIDUALLY ADJUSTABLE THERMALLYRESPONSIVE MEANS OPERABLE INDEPENDENTLY OF THE FIRST THERMALLYRESPONSIVE MEANS FOR CONNECTING SAID SIGNALLING